1. Field of the Invention
The present invention relates to a detection circuit and in particular to a detection circuit for detecting coil abnormality of a DC fan motor, which achieves the effects of effective real-time monitoring a fan and notification.
2. Description of Prior Art
With the progress of technology, the developing trend of electronic products is toward multi-function, miniaturization, and high operational security. However, with increasingly powerful electronic features, lots of heat generated during the operation becomes a problem. To overcome such a problem, a motor-driven fan device is used for the design of heat dissipation. Consequently, with the trend of electronic products miniaturization, the design of the fan motor also should tend toward miniaturization.
For a general communication case or electronic apparatus, large air flow is required to forcibly dissipate the generated heat. Thus, a number of fans are combined to form a fan module through which the heat generated within the communication case or electronic apparatus can be dissipated forcibly and quickly such that the electronic component therein can achieve the effect of stable operation. However, another problem is incurred. That is, when the coil of one fan in the fan module fails to rotate (e.g., an open circuit or a short circuit), the abnormal fan blade is affected by its surrounding air flow (i.e., affected by the air flow exhausted from the other fans) and can be continuously driven to rotate by its surrounding air flow such that the user can not immediately observe by eyes the damaged fan in the fan module. Alternatively, the Hall element in the abnormal fan is continuously rotated due to the rotation of the permanent magnet of the fan rotor, further normally providing the rotation speed signal for the controller which sends the signal to the external system. Accordingly, the damaged fan can not be found immediately. Hence, immediate replacement of the damaged fan and fan status monitoring can not be easily performed, further resulting in degradation of heat dissipation.
In summary, the prior art suffer from the following shortcomings:
1. The effect of immediate notification can not be achieved.
2. The effect of immediate fan status monitoring and fan replacement can not be achieved.
3. Heat dissipation is degraded.
Therefore, how to overcome the above problems and disadvantages is the focus which the inventor and the related manufacturers in this industry have been devoting themselves to.